Over the recent years, as enterprises have handled increasingly a larger quantity of data, and, e.g., cloud computing and other equivalent computing systems have spread in progress to provide flexibility to a change of system environment. When a cloud computing based system environment (which will hereinafter be termed also a cloud environment) suffers from a disaster and a damage due to a system failure, an execution environment and the data are migrated to another cloud environment for continuing tasks (the “task” is herein defined as a process executed on the cloud environment for businesses and services). In the cloud environment and other computer systems, a solution for continuing the tasks at occurrences of the disaster and other equivalent situations is called a Disaster Recovery (DR).
The DR prepares, in addition to an active operation site (which will hereinafter be termed a “real site”) to run the tasks, a site for taking a countermeasure against the disaster (which will hereinafter be simply termed a “disaster recovery site”) in order to migrate the tasks of the real site at the occurrences of the disaster and other equivalent situations. The disaster recovery site, which is prepared against the occurrences of the disaster and other equivalent situations, runs different tasks from those of the real site in terms of effectively utilizing resources. The tasks running on the disaster recovery site have lower priority levels than the tasks running on the real site in majority of cases.
The DR targeting on the cloud environment and other equivalent environments involves predefining the tasks on the real site, which are migrated to the disaster recovery site at the occurrences of the disaster and other equivalent situations, and some of tasks on the disaster recovery site, which are stopped for running the tasks on the real site. At the occurrences of the disaster and other equivalent situations, the tasks are switched over and stopped based on the predefinitions.